package DBLayer;

import java.sql.*;

/**
 * @Author (gruppe 5)
 * @Version 04-04-2013
 */

public class ConnectionDB
{ // constans used to get access to the database
	// SQL Server
	private static final String driver = "jdbc:sqlserver://balder.ucn.dk";
	private static final String databaseName = ";databaseName=dmaa0912_5";

	private static String userName = ";user=dmaa0912_5";
	private static String password = ";password=MaaGodt";

	private DatabaseMetaData dma;
	private static Connection con;
	// an instance of the class is generetated
	private static ConnectionDB instance = null;

	// the constructor is private to ensure that only one object of this class
	// is createt
	private ConnectionDB()
	{
		String url = driver + databaseName + userName + password;

		try
		{
			// load af driver
			// SQL Server
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
			System.out.println("Load af class ok");

		}
		catch (Exception e)
		{
			System.out.println("Can not find the driver");
			System.out.println(e.getMessage());
		}// end catch
		try
		{
			// connection to the database

			con = DriverManager.getConnection(url);
			// set autocommit
			con.setAutoCommit(true);
			dma = con.getMetaData(); // get meta data
			System.out.println("Connection to " + dma.getURL());
			System.out.println("Driver " + dma.getDriverName());
			System.out.println("Database product name " + dma.getDatabaseProductName());
		}// end try
		catch (Exception e)
		{

			System.out.println("Problems with the connection to the database");
			System.out.println(e.getMessage());
			System.out.println(url);
		}// end catch
	}// end constructor

	// closeDb: closes the connection to the database
	public static void closeConnection()
	{
		try
		{
			con.close();
			System.out.println("The connection is closed");
		}
		catch (Exception e)
		{
			System.out.println("Error trying to close the database " + e.getMessage());
		}
	}// end closeDB

	// getDBcon: Get-metode, returnerer forbindelsen til databasen
	public Connection getDBcon()
	{
		return con;
	}

	// this method is used to get the instance of the connection
	public static ConnectionDB getInstance()
	{
		if (instance == null)
		{
			instance = new ConnectionDB();
		}
		return instance;
	}

	public static void startTransaction()
	{
		try
		{
			con.setAutoCommit(false);
		}
		catch (Exception e)
		{
			System.out.println("fejl start transaction");
			System.out.println(e.getMessage());
		}
	}

	public static void commitTransaction()
	{
		try
		{
			con.setAutoCommit(true);
		}
		catch (Exception e)
		{
			System.out.println("fejl commit transaction");
			System.out.println(e.getMessage());
		}
	}

	public static void rollbackTransaction()
	{
		try
		{
			con.rollback();
			con.setAutoCommit(true);
		}
		catch (Exception e)
		{
			System.out.println("fejl rollback transaction");
			System.out.println(e.getMessage());
		}
	}
}// end DbConnection
